Silicone polymers containing UV photostabilizing groups

ABSTRACT

The present invention is directed to a series of silicone containing polymers that contain photostabilizers that act as photo stabilizers for Ultra Violet radiation. The polymers of the present invention are multi functional sun screening additives that allow in addition to photostabilizing the active sunscreen agent found in sunscreens, additionally provide high levels of UV protection in a cosmetically elegant base. The compounds are made by the reaction of a benzatriazole compound and a methyl ester silicone compound.

RELATED APPLICATIONS

This application is a continuation in part of co-pending U.S. Ser. No.14/120,763 filed Jun. 25, 2014, which in turn claims priority to andbenefit of U.S. Provisional Application Nos. 61/967,745, filed Mar. 26,2014, the disclosures of each of which are incorporated herein for allpurposes.

FIELD OF THE INVENTION

The present invention is directed to a series of silicone containingpolymers that contain photostabilizers that act as photo stabilizers forUltra Violet radiation. The polymers of the present invention are multifunctional sun screening additives that allow in addition tophotostabilizing the active sunscreen agent found in sunscreens,additionally provide high levels of UV protection in a cosmeticallyelegant base. Specific benzotriazole compounds are reacted with methylester containing silicone compounds to make esters. The resultingproducts are polymers by virtue of having been reacted with polymericsilicone compounds and provide photostability, improve skin aestheticsand better water resistance in formulation.

BACKGROUND OF THE INVENTION

The formulation of a high performance sunscreen product requires manyingredients. Most important of which is the sunscreen active. Sincesunscreens are considered by the Food and Drug Administration (FDA) as adrug, the actives that can be used are carefully regulated. Some ofthese materials do however experience photodegradation in formulation.It is the minimization of this type photodegradation issues that thepresent invention is directed.

Ultraviolet radiation from the sun or artificial sources can damagematerials and/or coatings containing photoactive substances, such asphotoactive polymers, pigments and dyes, by altering chemical bonds inthe structure of the polymer, pigment, or dye. This photodegradation canlead to color fading, loss of gloss, and/or loss of physical andprotective properties of a photodegradable or photoactive polymer orcoating. Understandably, photostabilizing or photostabilization is theprocess or effect of preventing the photodegradation of photoactivesubstances. In particular, photostabilizing can be increasing the lightfastness of a composition, preventing yellowing, or color formation, anddelaying or preventing photochemical reactions that adversely affectphotoactive substances.

One method to protect photoactive substances is through the use of UVfilters; one class of materials particularly suited to act as a UVfilters are naphthalate polyesters, for example those patented by thisassignee. Naphthalate polyesters are suitable UV filters because theyhave very high extinction coefficients and subsequently low transmissionof ultraviolet (UV) radiation. Additionally, the incorporation ofnaphthalates into polyester polymers increase the polymer's thermal andstructural stability, decrease the polymer's gas permeability, anddramatically block the transmission of UV radiation through the polymer.The UV filtering and improved physical characteristics have led to theuse of naphthalate polymers and blends in a wide range of applicationsincluding beverage and personal care product packaging, protectivescreening films, sail cloth fiber and as an additive stabilizer insunscreens and cosmetics.

While efficiently absorbing UV radiation, naphthalates dissipate (emit)the absorbed energy through fluorescence. Fluorescence is a type ofluminescence in which an atom or molecule emits radiation, i.e., aphoton, in passing from a higher to a lower electron state, as describedin my co-pending application Ser. No. 11/891,280 filed Aug. 9, 2007,herein incorporated by reference. The term is restricted to phenomena inwhich the time interval between absorption and emission energy isextremely short. This fluorescence can be a positive attribute inenabling the ready detection of naphthalate containing polymers or inthe development of fluorescent coatings and inks. Alternatively, thehigh absorption of UV radiation can produce color formation or yellowingafter exposure to UV light. Although this yellowing may not impactmechanical and physical properties of the polymer, it is generallyundesirable. The fluorescence, color formation, or yellowing phenomenaare of concern especially in packaging of products when the product'sappearance is to be as close to its natural state as desired. Forexample, in the packaging of foods and beverages, if food or beverageswere inside a poly(ethylene-2,6-naphthalene dicarboxylate) (“PEN”)container they may appear unnaturally colored.

Quenching fluorescence eliminates or reduces photon emission byproviding an alternative pathway for the excited state energy, such asradiative loss (heat), or intersystem crossing to an excited tripletstate. Methods to quench fluorescence in PEN have been disclosed, forexample see references cited in U.S. Pat. No. 6,001,952. These examplesdisclose the use of o-chlorophenol to quench PEN fluorescence inchloroform solutions. Dissolving PEN in a chloroform solution todisperse a fluorescence quencher, however, is not practical since thePEN must have a low molecular weight to dissolve in the chloroformsolution and only very dilute PEN solutions can be prepared.

Other compounds used to quench naphthalate fluorescence include:benzotriazoles, cyanoacrylates, benzophenones, and benzoxazinones (JPPat. No. 08225672); cyclic imino esters or quinoxalines (EP Pat. No.0711803); and benzylidene compounds (U.S. Pat. Nos. 4,617,374,4,707,537, and 6,001,952). Many of these examples are disadvantageousbecause they require postproduction coating of fluorescent materials,show inadequate reduction in the fluorescence from fluorescentmaterials, or are only effective in very dilute solutions. Accordingly,there is a need for naphthalate compositions having a reducedfluorescence without deleteriously affecting the physical properties ofthe polymer.

The absorption of ultraviolet light by a chromophore-containing organicmolecule causes the excitation of an electron in the chromophore moietyfrom an initially occupied, low energy orbital to a higher energy,previously unoccupied orbital. The energy of the absorbed photon is usedto energize an electron and cause it to “jump” to a higher energyorbital, see Turro, Modern Molecular Photochemistry, 1991. Two excitedelectronic states derive from the electronic orbital configurationproduced by UV light absorption. In one state, the electron spins arepaired (antiparallel) and in the other state the electron spins areunpaired (parallel). The state with paired spins has no resultant spinmagnetic moment, but the state with unpaired spins possesses a net spinmagnetic moment. A state with paired spins remains a single state in thepresence of a magnetic field, and is termed a singlet state. A statewith unpaired spins interacts with a magnetic field and splits intothree quantized states, and is termed a triplet state.

In the electronically excited state, the chromophore-containing organicmolecule is prone to degrade via a number of known pathways and,therefore, can absorb little or no additional UV light. Tophotostabilize an electronically excited chromophore-containing organicmolecule in order to provide sufficient UV protection, it must bereturned to the ground state before it undergoes a photochemicalreaction destructive to its UV absorbing capability. There are knownphotostabilizing sunscreen additives, such as Octocrylene,methylbenzilydene camphor, and the esters or polyesters of naphthalenedicarboxylic acid of this assignee's U.S. Pat. Nos. 6,113,931;6,284,916; 6,518,451; and 6,551,605, all hereby incorporated byreference, that are capable of quenching excited triplet state energy.Alkoxy crylenes, particularly methoxy crylenes, returnchromophore-containing organic molecules, particularly butylmethoxydibenzoylmethane (Avobenzone), octyl methoxycinnamate(Octinoxate), and octyl salicylate (Octisalate), from both anelectronically excited singlet state and excited triplet state back totheir ground state, thereby photostabilizing the UV-absorbing organicmolecules.

A compound known to those skilled in the art is iscotrizinol. Thismaterial sold under the trade name Unasorb ET by 3V Sigma, has thefollowing structure and identifiers.

The product has the following properties reported by 3V Sigma themanufacturer.

Chemical and Physical Characteristics INCI Name: Ethylhexyl TriazoneIUPAC Name: 4,4′-[[6-[[4-[[(1,1-dimethylethyl)amino]-carbonyl]phenyl]amino]-1,3,5-triazine-2,4- diyl]diimino]bis-,bis(2-ethylhexyl)benzoate CAS Number: 154702-15-5 Empirical Formula:C₄₈H₆₆N₆O₆ Molecular Weight: 823.0 Appearance: Whitish Powder MeltPoint: <132.0 Specific Extinction: (at 314 nm in Ethanol) Solubility (%w/w at 25° C.) PEG-7 Glyceryl ca. 10 Cocoate: Diisopropyl Adipate: ca. 9C12-15 Alkyl Benzoate: ca. 4 Caprylic/Capric ca. 4 Triglyceride:Isopropyl Palmitate: ca. 2 Mineral Oil:  <1

The referenced works establish the long felt need for photostabilizingpolymers that are both efficient and effective. The need is primarily inthe region of UVA. It is to this area that the current invention isdirected. The specific polymers of the present invention result inproducts, which not only ameliorate the inherent photo instability, butalso form films on the surfaces to which they are applied which arewater resistant and stay in place increasing effectiveness andefficiency.

All references cited are incorporated herein by reference.

THE INVENTION Object of the Invention

The present invention has as its object a series of silicone polymersthat contain two specific benzotriazole ultraviolet photostabilizingmoieties that are used to enhance the photostability of sunscreenformulations, specifically in the UVA region of the sunscreen spectrum.

Additionally, another object of the present invention is to providespecific polymers for use in sun screening applications.

Still another object of the present invention provides a process forprotecting skin from the deleterious effects of the sun which comprisescontacting the skin with an effective sun screening concentration of apolymer, which is produced using the current invention.

Other objects of the invention will become clear as one reads andunderstands the disclosure of the present invention.

All temperatures given are in degrees C., all percentages arepercentages by weight and all references are incorporated herein byreference as allowed.

SUMMARY OF THE INVENTION

The present invention discloses a series of silicone polymers thatcontain two specific benzotriazole ultraviolet photostabilizing groupthat can be used to enhance the photostability of sunscreenformulations, specifically in the UVA region of the sunscreen spectrum.

One starting raw material has the following structure:

It is described as benzotriazole Ultraviolet Light Absorber, having thechemical name 2-(2-hydroxy-5-tert-octylphenyl) benzotriazole. It has theformula of C₂₀H₂₅N₃O and the CAS number of 3147-75-9.

The second starting raw material has the following structure:

It is described as a benzotriazole Ultraviolet Light Absorber. It hasthe chemical name2-[2-hydroxy-3,5-di-(1,1-dimethylbenzyl)]-2H-benzotriazole, the formulaC₃₀H₂₉N₃O. The CAS number is 70321-86-7. It is available from Mayzo Incis Swaunee Ga. as BLS 234.

The OH group on the compounds are reacted with specific siliconecompounds. The silicones suitable for the synthesis of esters of thestarting materials are selected from the group consisting of:

wherein x is an integer from 0 to 10;

wherein:

-   -   a is an integer ranging from 0 to 20;    -   b is an integer ranging from 1 to 10.

The esters have one the following structures:

wherein x is an integer from 0 to 20;

wherein

-   R is selected from the group consisting of:

and

-   (iii)-   mixtures thereof.

PREFERRED EMBODIMENTS

In a preferred embodiment R is

In a preferred embodiment R is

In a more preferred embodiment R is a mixture of;

In a preferred embodiment x is 1.

In a preferred embodiment x is 2.

In a preferred embodiment x is 5.

In a preferred embodiment x is 10.

In a preferred embodiment x is 0.

In a preferred embodiment x is 20.

In a preferred embodiment a is 0.

In a preferred embodiment a is 5.

In a preferred embodiment a is 10.

In a preferred embodiment a is 15.

In a preferred embodiment a is 20.

In a preferred embodiment b is 1.

In a preferred embodiment b is 5.

In a preferred embodiment b is 10.

In a preferred embodiment b is 15.

In a preferred embodiment b is 20.

Raw Materials EXAMPLE 1 Benzenetriazole 1

Benzenetriazole 1 has the following structure;

It is described as benzotriazole Ultraviolet Light Absorber, having thechemical name 2-(2-hydroxy-5-tert-octylphenyl) benzotriazole. It has theformula of C₂₀H₂₅N₃O and the CAS number of 3147-75-9. It is availablefrom Mayzo Inc of Swaunee Ga. as BLS 5411.

EXAMPLE 2 Benzenetriazole #2

Benzenetriazole 2 has the following structure;

It is described as a benzotriazole Ultraviolet Light Absorber. It hasthe chemical name2-[2-hydroxy-3,5-di-(1,1-dimethylbenzyl)]-2H-benzotriazole, the formulaC₃₀H₂₉N₃O. The CAS number is 70321-86-7. It is available from Mayzo Incis Swaunee Ga. as BLS 234.

Silicone Polymers

One class of silicone polymers useful as raw materials in thepreparation of the polyesters have the following structure:

wherein x is an integer from 0 to 10;

These materials are items of commercially available from Siltech LLC,Lawrenceville Ga. under the trade name Silmer UME.

Examples x 3 0 4 1 5 2 6 5 7 10 8 20

The second class of silicone polymers useful as raw materials in thepreparation of the polyesters have the following structure:

wherein:

-   -   a is an integer ranging from 0 to 20;    -   b is an integer ranging from 1 to 10.

These materials are items of commercially available from Siltech LLC,Lawrenceville Ga. under the trade name Silmer UME.

Example a b 9 0 1 10 5 10 11 10 5 12 15 15 13 20 20 14 0 20 15 20 1

Polymers of the Present Invention

General Procedure

In a suitable reaction flask capable of heating the contents to 200° C.is added the specified number of grams of the specified Benzenetriazole(Example 1 or 2), the specified number of grams silicone (Examples3-15). The reaction is heated to 170-180° C. During the heating time andonce the reaction reaches around 140° C. methanol begins to distill off.The temperature if held between 170 and 180° C. for 5 hours, then thereaction is followed by acid value, which drops during the reaction thenstabilizes.

Benzenetriazole Silicone Example Example Grams Example Grams 16 1 323 3280 17 2 447 4 317 18 1 323 5 354 19 2 442 6 465 20 2 447 7 650 21 1 3238 1020 22 2 447 9 437 23 1 323 10 326 24 2 447 11 453 25 1 323 12 358 262 447 13 355 27 1 323 14 281 28 2 447 15 1917 29 1 161.5 15 1917 2 223.5

The compounds are used without purification.

The compounds of the present invention photostabilize sunscreens whenadded to sun screen formulations at a concentration of between 1 and 10%by weight.

Example 29 has both the benzatriazole compounds present. It provides thebest photostability.

While the illustrative embodiments of the invention have been describedwith particularity, it will be understood that various othermodifications will be apparent to and can be readily made by thoseskilled in the art without departing from the spirit and scope of theinvention. Accordingly, it is not intended that the scope of the claimsappended hereto be limited to the examples and descriptions set forthhereinabove but rather that the claims be construed as encompassing allthe features of patentable novelty which reside in the presentinvention, including all features which would be treated as equivalentsthereof by those skilled in the art to which the invention pertains.

I claim:
 1. An ester having the following structure:

wherein x is an integer from 0 to 20; R is selected from the groupconsisting of: (i)

(ii)

and (iii) mixtures thereof.
 2. The ester of claim 1 wherein x is
 1. 3.The ester of claim 1 wherein x is
 5. 4. The ester of claim 1 wherein xis
 10. 5. The ester of claim 1 wherein x is
 0. 6. The ester of claim 1wherein x is 20.